Sn-mesoporphyrin (SnMP) is a synthetic heme analogue which is used to control heme catabolism by inhibiting heme catabolism and thus bilirubin production in premature babies with severe jaundice. Clinical trials in 517 newborns demonstrate that SnMP in a dose related manner significantly ameliorated the course of hyperbilirubinemia in these infants. In addition with a SnMP dose of 6mmol/kg body weight, the peak incremental bilirubin was reduced by 41% and the phototherapy requirements were decreased by 76% compared to control infants. Mass Spectrometry is used to ensure the integrity of the drug.